The heart of a computer is a magnetic hard disk drive (HDD) which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
The volume of information processing in the information age is increasing rapidly. In particular, HDDs have been desired to store more information in its limited area and volume. A technical approach to this desire is to increase the capacity by increasing the recording density of the HDD. To achieve higher recording density, further miniaturization of recording bits is effective, which in turn typically requires the design of smaller and smaller components, along with a reduction in the flying height of the head over the magnetic disk.
The reduction in flying height of the head over the magnetic disk under high humidity conditions is problematic because it leads to read/write instability in HDDs. Japanese Provisional Application No. JP10-14386 describes a technology for improving the contact start/stop (CSS) durability under high temperature/high humidity conditions by applying a lubricant layer having a perfluoropolyether (PFPE) lubricant and a lubricant with a cyclophosphazene group. However, the surface force, a measure of interaction between planes in near contact, of the lubricant layer prepared by the above-mentioned technology remarkably increases with a corresponding increase in humidity. Therefore, this makes it difficult to reduce the distance between head and the disk with state-of-art lubricant layers because the increase in the surface force leads to flight instability of the head during operation. The reduction in the distance between head and disk is a prerequisite to increasing the recording density of HDDs.